adg Posted February 21 Report Share Posted February 21 Hi I'm having issues with my carb on my 720, I think it's mostly vacuum but I just wanna get rid of the egr and the other emissions stuff just too many vacuum lines but I wanna still run with the stock Hitachi carb, I was mostly wondering if deleting the egr would mess with my altitude compensation it's a California model so it's got all of that dumb emissions stuff I just wanna remove all the vacuum stuff that doesn't have to be there besides the compensator. Quote Link to comment
Stinky Posted February 22 Report Share Posted February 22 If your hoses don't look new....change them all out. I don't know nutN about how the compensation works. I would assume not. I assume that they are 2 dif operations. Removing the EGR will enrich your fuel mixture. Quote Link to comment
datzenmike Posted February 22 Report Share Posted February 22 The EGR adds small measured amounts of inert exhaust. (exhaust that has almost no oxygen content as it has been mixed with fuel and burned in the normal combustion process) The introduced exhaust simply takes up space in the combustion chamber reducing combustion temperatures that form nitrogen oxides. There is no EGR at idle or full throttle so performance is unaffected. EGR only acts on part throttle running. The normal air to fuel ratios are not affected, it doesn't run richer or leaner. EGR removal shouldn't affect the altitude compensation. If you live in an area of changing elevations (thousands of feet) a carburetor runs richer as you go higher and leaner when you descend. It would probably save a little fuel. EGR... You don't have to delete it just pull the small rubber hose off to deactivate it. You can remove the EGR valve, but then you have to make a block off plate and a gasket that might leak later. Then you have to seal the pipe connected to the exhaust manifold. You can cut and crush and roll the pipe to seal it or remove and use a pipe plug or weld the hole. Quote Link to comment
adg Posted February 29 Author Report Share Posted February 29 Also I've been thinking about attempting a turbo small just so i can get a little more then the stock 86hp, but I don't want to crowd the engine bay more and am thinking about putting the turbo in the rear but at most I'm worried about the engine being able to take it as it's stock but its already having issues idling at 2000 and won't go down no matter what I've done its all original with 150000 miles on it I just don't wanna have to rebuild it if I turbocharge it and it can't take it Quote Link to comment
datzenmike Posted February 29 Report Share Posted February 29 You can't be thinking of a turbo if the engine is not idling properly. Fix this first and it will probably restore much of your lost power. Overly fast idle. Needs two things... more air and more fuel. So fuel and air are getting in somewhere. 1/ There is a fast idle function when the choke is on. On a warmed up engine, take the top off the air filter and look at the choke plate. Is it closed or open? OPEN CLOSED On the warm engine it should be fully open like the first picture. Find this fast idle cam above the throttle cable. Hold the throttle half open and by hand open and close the choke. This little plastic thing should move in and out of the way of the closing throttle. It could be stuck in the on position and holding the throttle open. Fast idle is 1,800-2,200 RPM. Spray WD-40 all over the linkages and work them back and forth to free them 2/ look down inside the carburetor with a flashlight. Look down into the secondary and make sure that it is closed fully and that nothing is caught in it preventing it from closing. If not completely closed, air and fuel will get in speeding up the idle. Now look down the primary and adjust the idle speed screw and make sure that it can also be closed all the way. If it is completely closed go to 3/ below... 3/ Find the BCDD (above) on the valve cover side of your carburetor. In the center is a rubber plug. Remove and adjust the screw inside a couple of turns counter clockwise. This will decrease the sensitivity and reset the turn off for the 'fast idle'. Keep track of the turns so if this doesn't help you can return it to it's original setting. If this removes the fast idle it will likely stall because the idle speed screw was turned down all the way. Reset your idle speed. Quote Link to comment
adg Posted February 29 Author Report Share Posted February 29 I don't have a rubber plug on the bcdd it's a vacuum line instead and it goes to the vacuum peice on top of the thermostat housing, what does that do instead? Quote Link to comment
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